Microfluidic Chip Liquid Inlet Design for Low-Resistance Droplet Transfer
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Solution Overview
Problem
Existing microfluidic chips face challenges in efficiently reducing motion resistance of droplets, particularly when transitioning from a liquid storage region to a detection region, which affects the movement and control of droplets.
Innovation Solution
The microfluidic chip design includes a liquid storage tank with an inclined side wall and a liquid inlet configuration that minimizes motion resistance by aligning the liquid inlet with the detection region, utilizing an interlayer dielectric layer to enhance droplet support, and incorporating a hydrophobic layer to facilitate droplet movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional vertical liquid inlet configuration is used, then the chip structure is simple, but the droplet motion resistance is high and droplet transfer efficiency is poor
Solution Approach 1:
The liquid inlet is designed with an asymmetric inclined configuration where the inlet axis forms an angle θ with the normal direction of the storage tank bottom. This asymmetric arrangement optimizes the droplet transfer path, reducing motion resistance and improving transfer efficiency without requiring complex additional structures.
Solution Approach 2:
The liquid inlet configuration extends into a third dimension by creating an inclined angle relative to the vertical axis. This dimensional change allows the liquid to enter the storage tank at an optimized angle, facilitating smoother droplet movement and reducing resistance during the transfer from storage to detection region.
2Productivity
If the liquid inlet is far from the detection region, then the storage capacity is sufficient, but the droplet transfer path is long and motion resistance increases
Solution Approach 1:
The inclined liquid inlet creates a curved transfer path for droplets compared to a straight vertical drop. This curved configuration allows the droplet to roll or slide along the inclined surface, reducing impact forces and motion resistance while maintaining a relatively short transfer distance to the detection region.
3Quantity of substance
If the liquid storage tank has large volume, then the storage capacity is sufficient, but the motion resistance of droplets increases when transitioning to detection region
Solution Approach 1:
The inclined configuration of the liquid inlet creates an asymmetric entry point that positions the liquid flow optimally relative to the detection region. This asymmetric arrangement reduces the distance and resistance droplets must overcome when transitioning from the large-volume storage tank to the detection region, despite the tank's large storage capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively reduces droplet motion resistance, allowing for efficient transfer of droplets from the storage region to the detection region, enhancing the control and automation of droplet operations.
Implementation Method 1
an angle between the extending direction of the line connecting the first end point and the second end point and the axial direction of the liquid inlet is θ: tan θ>2d(F−G)/ε0εrV2, where ε0 represents a vacuum dielectric constant; εr represents a relative dielectric constant of the interlayer dielectric layer; d is a thickness of the interlayer dielectric layer; F represents a support force applied by the interlayer dielectric layer on a droplet to be detected; G represents the gravity of the droplet to be detected; V represents a voltage value applied to the second electrode layer
Implementation Method 2
incorporating a hydrophobic layer to facilitate droplet movement
Implementation Method 3
Digital Microfluidics (DMF) utilizes the electrowetting principle of droplets on a hydrophobic surface, and applies a control signal to an electrode array to cause a contact angle of the droplets to change
Data Source
AI summary
The present disclosure provides a microfluidic chip, and belongs to the field of biological detection technology. The microfluidic chip is divided into a middle region and a peripheral region surrounding the middle region; the middle region includes a liquid storage region and a detection region; the microfluidic chip includes a first substrate and a second substrate opposite to each other; the first substrate includes a first base plate and a first electrode layer; the second substrate includes a second base plate and a second electrode layer; wherein a liquid storage tank and a liquid inlet are on a side of the first base plate proximal to the second substrate, the liquid inlet penetrates through a bottom of the liquid storage tank; the liquid storage tank and the liquid inlet are both in the liquid storage region.